SAN FRANCISCO: Prophet's annual corporate reputation study found BP and Toyota tumbled to the bottom of its rankings while General Motors climbed back up the list.

BP fell from a rank of 78 in 2009 to a rank of 145 and Toyota fell to 139 from 18. General Motors moved from 123 to 85. The study polled 4,900 US consumers about 145 Fortune 500 companies in 18 industry sectors for the 2010 calendar year.

“Toyota had an unbelievable plummet, by far the biggest we've seen,” said Jeff Smith, partner at Prophet. “The real story over the next couple of years is going to be how long it will take Toyota to climb back up from a reputational perspective.”

Smith added, the fall of Toyota and BP is indicative of a shift in what is driving corporate reputation. In 2009, he said, it was factors such as products and service quality. In 2010, factors such as ethics and transparent communication were the drivers.

For industry sectors, consumer packaged goods and technology were two areas that captured a high level of consumer trust and oil and gas, healthcare, and financial services saw a drop in trust.